Former Florida Governor Jeb Bush on Monday announced his bid for the Republican presidential nomination.

“My message will be an optimistic one because I am certain that we can make the decades just ahead in America the greatest time ever to be alive in this world,” Bush, the son and brother of two former presidents, told a crowd in Miami, Florida.

Once thought the frontrunner for the Republican nomination, Bush has stumbled in recent weeks over the Iraq War.

His announcement makes him the 11th Republican candidate vying for the White House.

Like all of his Republican rivals for the GOP nomination, Bush does not support marriage equality. (Former New York Governor George Pataki has not publicly stated his position on the issue, saying only that the issue of marriage should be left up to the states. As governor, he signed a gay protections bill.)

As recently as last month, Bush said that he does not believe that gay couples have a constitutional right to marry and that he supports the rights of businesses to deny services to gay men and lesbians based on their “moral beliefs.”

“A big country – a tolerant country – ought to be able to figure out the difference between discriminating someone because of their sexual orientation and not forcing someone to participate in a wedding that they find goes against their moral beliefs. We should be able to figure this out. This should not be that complicated. But gosh, it is right now,” Bush told Christian broadcaster CBN's David Brody.

(Related: Jeb Bush: “Hard to fathom” need for marriage equality.)